Creeping buttercup identification and control

Why it's a problem

Creeping buttercup is a widespread weed of concern throughout King County. This plant is aggressive and able to spread over 40 square feet in 1 year. It takes potassium, an important nutrient, from the soil, having a negative effect on surrounding plants. Fresh plants are moderately toxic to some grazing animals including horses.

Plant description

Creeping buttercup is native to Europe, Asia, and northwestern Africa. Creeping buttercup is a low-growing perennial with horizontal stems (stolons) that spread and root outwards from a parent plant. New plants grow from these rooted stems, spreading the infestation outwards.

Leaves are dark green with pale patches, each leaf is somewhat triangular, divided into 3 toothed leaflets, and fuzzy to the touch.

Stems are hollow and hairy or fuzzy. Plants can reach up to 1 foot tall. 

Flowers are bright yellow with 5 glossy petals. Bloom time is from March to August. 

Fruits are small and each contain one seed (known as achenes). They grow in clusters that form spiky-looking round heads.

Be aware of look-alike plants

Creeping buttercup is often confused with:

Tall buttercup

Buttercup family

When in doubt, take photos and report them on iNaturalist.

What to do if you find it

Because creeping buttercup is so widespread, property owners in King County are not required to control it. We can provide advice on how to control creeping buttercup, but there is generally no legal requirement to do so. Control is recommended where animals are grazing and in natural areas being restored to native plants, where feasible.

Control methods

We recommend using a combination of methods to control weeds. In areas with few weeds, it is important to act quickly before they become harder to control. Make a long-term plan as it often takes several years to get rid of most weeds. Start in the least infested areas first and then move into more heavily infested areas.

In lawns and pastures, promote healthy grass by over-seeding, fertilizing as needed, and not over-grazing. Adding lime can improve grass health and keep buttercup from re-establishing. However, lime won’t control buttercup that is already well-established.

Improve soil drainage. Reduce compaction by aerating and avoid trampling when soils are wet.

Clean mowers and other equipment to avoid spreading buttercup seeds to un-infested areas.

While doing control, protect native and beneficial species. 

Manual control

Digging is most effective from fall to spring while the soil is not hard, and roots won’t break off as much. 

Stem and root fragments left behind can produce new plants, be careful to remove all roots and plant runners.

Disturbance of the soil can increase seed germination. Seeds can live in the soil for 20 years or longer, so keep an eye on the area even if only removing a few plants.

Mechanical control

Mowing is not effective. Creeping buttercup’s growing point is at soil level, so plants resist mowing and quickly re-sprout when cut.

Regular cultivation can kill the buttercup, but it will likely come back if regular cultivation stops.

Chemical control

Stay safe when using herbicide:

• Always read the label before use.
• Wear a long-sleeved shirt, long pants, shoes, and eye protection.
• Follow state and local regulations.

Glyphosate (for example, Roundup and Aquamaster) can be applied to actively growing plants before they seed. Glyphosate is “non-selective” and can harm non-targeted plants and grasses.

“Selective” broadleaf herbicides will kill the buttercup without harming surrounding grasses. Products containing the active ingredient MCPA are most effective on buttercup. Herbicides with the active ingredients metsulfuron (Escort, Ally) and aminopyralid (Milestone) are also effective but can harm some grasses and other plants if not used correctly.

It will probably take at least two or three applications to completely get rid of creeping buttercup. This is because many seeds survive in the soil even after the plants are treated. Also, some mature plants will recover from the treatment.

Monitor the treated area for re-growth and pull up any new seedlings before they establish runners. Re-seed or re-plant bare areas after removing buttercup to keep it from re-infesting the area.

See the PNW Pest Management Handbook for the most up to date and specific method for chemical control of creeping buttercup. 
 
Avoid spraying where there is a chance that herbicide will enter a waterway or wetland unless you are using a state-approved aquatic herbicide and have the required permits and licenses to do so. Use of pesticides in water is regulated in Washington state. See Washington Department of Ecology Aquatic Pesticide Permits for details.  

Disposal instructions

Plants that do not have flowers or seeds can be put into yard waste bins. We don’t recommend home composting because plants can regrow from roots and runners. These plants can also be left on thick cardboard or tarps and left out to dry. Once dried, you can spread the plant matter as mulch in the area where it had been growing (again, only if seeds and flowers are not present).

Plants that have flowers or seeds should be bagged and disposed of in the garbage.

Noxious Weed Disposal - Washington State Noxious Weed Control Board

Are your weeds piling up? - Noxious Weeds Blog